Morning hypertension in Asian populations

Hypertension remains the leading cause of cardiovascular morbidity and mortality across continents.1 Blood pressure (BP)–lowering treatment is associated with reduction of major cardiovascular events and mortality2 and this observation is extended to Asian populations.3 The Consensus Statement of an Asian Expert Panel presented in this issue of the Journal of Clinical Hypertension focused on the management of morning hypertension may stimulate further research in the field and promote the concept that this phenotype of hypertension can be a complementary clinical tool for decision-making.4 Some of the authors of this Asian Expert Panel extensively reviewed this topic elsewhere a few months ago.5 This statement seems timely because much of the research on morning hypertension has been performed in Asian populations and because the prevalence of this phenotype is higher in Asians compared with their European counterparts.6 Also, stroke is more prevalent in Asia compared with all other geographical regions, and incident episodes are mostly distributed in the early morning hours.7, 8 Under these considerations, this statement on the management of morning hypertension in Asia4 might have important healthcare consequences. Morning hypertension should be seen as an integrated phenotype of two different hypertension conditions. The first one is the early-morning surge phenotype in which a marked increase in BP is noticed at arising and 1 to 2 hours after arising. The second one is the nighttime progressive elevation in BP that is extended in the morning and persists for a few of hours after awaking.5 Although hypertensive BP levels are getting established for a short period in the morning and can be attested with out-of-clinic BP measurements in each of these conditions, it is less clear whether morning hypertension will resolve until a programmed morning clinic BP evaluation. Authors suggest,4 however, that morning clinic BP evaluation can be used as a screening tool for the diagnosis of morning hypertension. Although this clinical proposal based on expert opinion may be used in patients with their clinic visit in the morning hours, what should be the recommendation for patients with their clinic visit in the afternoon and how can an underlying masked morning hypertension phenomenon be excluded? In our opinion, instead of the usual recommendations for home or ambulatory BP measurements, patients should be instructed to measure their morning BP within an hour from waking or to have two different morning BP measurements—the first one close to waking and the second one several hours later after awaking. Another question of interest is to what extent morning hypertension is reproducible for the same patient during different days of the week and different seasons of the year. It is suggested, as acknowledged in the present Consensus Statement, that in the first working day of the week or during colder periods of the year, the prevalence of morning hypertension might be higher compared with all other weekdays or seasons, respectively.9, 10 Moreover, as hypertension comorbidities such as obesity, diabetes mellitus, sleep apnea, and already established cardiovascular disease are highly associated with morning hypertension, an out-of-clinic BP evaluation seems reasonable to confirm the diagnosis of morning hypertension in these populations.11 An important aspect of morning hypertension is related to antihypertensive treatment. Indeed, the morning hours close to rising (before and after) have been associated with high prevalence of cardiovascular events.8 Thus, it is important that hypertension be controlled especially during these hours of cardiovascular vulnerability. However, cardiovascular vulnerability is also extended to earlier hours during nighttime sleep.12 Practically, this means that BP control should cover both nighttime and early morning. The diagnosis of uncontrolled morning hypertension (in already treated patients) may change the treatment strategy in these patients but can also be used as a complementary clinical tool for treatment decisions. For example, morning hypertension can be associated with either nighttime normotension (eg, in the elderly, those with Parkinson disease), normal 24-hour averaged BP levels (eg, in patients with isolated nighttime hypertension with newly established sleep apnea), or sustained BP elevation over the whole day. In these three clinical situations, antihypertensive treatment should be different. When antihypertensive treatment potentiation is planned to control morning hypertension, time of drug administration, dosing, biological drug half-life, and free or fixed-dose combination treatments should be considered. Finally, salt intake and continuous positive airway pressure may have a discrete role in patients with volume-dependent hypertension and sleep apnea, respectively. Based on observational evidence, morning hypertension can be considered a trigger for increased cardiovascular risk.5 However, observational evidence can only be used as a rising-hypothesis instrument because many demographic and clinical characteristics are largely different between groups. Well-designed randomized controlled clinical trials are needed to address whether regression of morning hypertension is associated with better hard end point outcomes. A reanalysis (with preserved randomization) of completed trials (eg, SPRINT [Systolic Blood Pressure Intervention Trial], HOPE [Heart Outcomes Prevention Evaluation], HOMED-BP [Hypertension Objective Treatment Based on Measurement by Electrical Devices of BP], VALUE [Valsartan Antihypertensive Long-Term Use Evaluation], ASCOT [Anglo-Scandinavian Cardiac Outcomes Trial])13-17 with baseline and attained ambulatory or home BP data, on an individual basis, might provide some answers in the field. However, the main burden with a reanalysis of previous trials is that most patients were treated at baseline with different antihypertensive regimens. Thus, the prevalence of morning hypertension in already treated patients is expected to be largely underestimated. Thus, randomized controlled trials in patients without baseline treatment are needed to deliver strong evidence for the role of morning hypertension on cardiovascular protection. Morning hypertension in Asian populations should be promptly diagnosed because it represents a clinical element of heightened cardiovascular risk. Whether treatment of morning hypertension is associated with better cardiovascular outcomes needs to be determined by appropriate randomized controlled trials. None. None.